JPH11278227A - Brake control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the appropriate coping in the case where starting condition of the brake steering control and the brake assist control are satisfied at the same time by providing a simultaneous control means for adding each target control variable so as to control the braking force of a selected wheel on the basis of the added variable. SOLUTION: In order to restrict the over-steering and under-steering of a vehicle, a hydraulic control valve means is controlled on the basis of a first target control variable. A brake assist control means for performing the brake assist control, for controlling the hydraulic control valve means on the basis of a second target control variable, and for controlling the brake liquid pressure of each wheel cylinder Wfr, Wfl, Wrr, Wrl is provided. In the case where the starting condition of the brake steering control and the brake assist control are satisfied at the same time, since the braking force of control overlapped wheels FR, FL, RR, RL are controlled on the basis of the added variable of the first target control variable for brake steering control and the second target control variable for brake assist control, both the control can be carried out without a necessity of selecting the control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake steering control for suppressing oversteer or understeer of a vehicle by braking a wheel and a brake control device for a vehicle capable of executing a brake assist control.

[0002]

2. Description of the Related Art During traveling of a vehicle, for example, during emergency braking, a brake pedal is depressed at a rapid speed. However, the pedaling force is insufficient or it is difficult to maintain the pedaling force, so that an appropriate braking force may not be obtained. In light of this, recently,
It has been proposed to add a brake assist control function,
Already installed in some commercial vehicles. This brake assist control automatically increases the braking force when the brake pedal is depressed at a rapid speed to assist the driver in operating the brake pedal. Generally, the boosting function of the vacuum booster is used. Control is being done.

Here, for the purpose of completely or partially saving the vacuum booster, there is a technology for performing brake assist control using a pump for anti-skid control or traction control (Japanese Patent Laid-Open No. 8-230634). Are known. Specifically, this includes a wheel cylinder, a master cylinder, a main hydraulic pressure path connecting the master cylinder to the wheel cylinder, and a modulator disposed in the main hydraulic pressure path to control the brake hydraulic pressure of the wheel cylinder. A first on-off valve for opening and closing a main hydraulic path between the modulator and the master cylinder, and a discharge side connected between the first on-off valve and the wheel cylinder to discharge pressurized brake fluid to the wheel cylinder. A hydraulic pump, an auxiliary hydraulic pressure path connecting the suction side of the hydraulic pump to the master cylinder, and a second on-off valve for opening and closing the auxiliary hydraulic pressure path. A pressure sensor for detecting an output hydraulic pressure of the master cylinder is provided. When the master cylinder hydraulic pressure is equal to or higher than a predetermined hydraulic pressure and the increasing rate of the master cylinder hydraulic pressure exceeds a predetermined ratio, the hydraulic pump and the first And the second on-off valve is controlled, and the brake assist control is performed.

On the other hand, recently, a braking steering control device that prevents excessive oversteer or excessive understeer of a vehicle by braking a wheel has also attracted attention. The braking steering control includes an oversteer suppression control that applies a braking force to a front outer wheel when the vehicle turns excessively oversteer when the vehicle turns, and an oversteer suppression control that suppresses the oversteer when the vehicle turns. When the vehicle tends to understeer, the vehicle is classified into understeer suppression control that suppresses understeer by applying a braking force to the turning inner rear wheel. Such braking steering control is not described in the above-mentioned publication, but can be performed using a hydraulic circuit shown in this publication. That is,
For example, in the case of oversteer suppression control, the hydraulic pump for the turning outer front wheel, the two on-off valves, and the modulator are controlled, and the brake fluid in the master cylinder is supplied to the wheel cylinder mounted on the turning outer front wheel by the hydraulic pump. The pressure is increased and the brake fluid pressure of the wheel cylinder is controlled by the modulator.

[0005]

However, when the above-mentioned publication is configured so that the brake steering control can be executed, if the brake steering control and the brake assist control simultaneously satisfy the start conditions for the same wheel, appropriate measures are taken. It is difficult. As described above, the above-mentioned publication does not describe a countermeasure for a case where the braking steering control and the brake assist control simultaneously satisfy the start condition.

Therefore, an object of the present invention is to appropriately cope with a case where the start conditions of the braking steering control and the brake assist control are simultaneously satisfied.

[0007]

According to a first aspect of the present invention, there is provided a vehicle braking control device for detecting a motion state detecting means for detecting an oversteer or an understeer of a vehicle. Based on the detection result of the means, select a control wheel from a plurality of wheels, set a first target control amount for the selected wheel, based on the first target control amount to suppress oversteer or understeer of the vehicle Brake steering control means for controlling the braking force of the selected wheel, brake operation amount detection means for detecting a value related to the operation amount of the brake pedal, and brake assist control based on the detection result of the brake operation amount detection means, The brake assist control means for controlling the braking force of each wheel based on the second target control amount, and the brake steering control and the brake assist control are simultaneously opened. When the start condition is satisfied, a simultaneous control means for adding the first and second target control amounts and controlling the braking force of the selected wheel based on the added amount is provided.

According to the first aspect of the present invention, when the braking steering control and the brake assist control simultaneously satisfy the start condition, the first target control amount for the brake steering control and the second target control amount for the brake assist control. Since the braking force of the control overlapping wheel is controlled based on the added amount of the control, it is not necessary to select any control, and both controls can be performed reliably.

[0009] To solve the above technical problem, a second aspect of the present invention is provided.
The present invention provides a vehicle brake control device comprising: a plurality of wheel cylinders mounted on a plurality of wheels of a vehicle for applying a braking force; a hydraulic pressure generating device for generating a hydraulic pressure in response to an operation of a brake pedal; Hydraulic pressure control valve means disposed between the generator and the wheel cylinder for controlling brake fluid pressure of the wheel cylinder, motion state detecting means for detecting oversteer or understeer of the vehicle, and detection of the motion state detection means Based on the result, a control wheel is selected from the plurality of wheels, a first target control amount for the selected wheel is set, and the fluid is controlled based on the first target control amount to suppress oversteer or understeer of the vehicle. Brake steering control means for controlling pressure control valve means for controlling brake fluid pressure of a wheel cylinder mounted on the selected wheel, and operation of the brake pedal A brake operation amount detecting means for detecting a value relating to an amount; a brake assist control based on a detection result of the brake operation amount detecting means; controlling the hydraulic pressure control valve means based on a second target control amount; If the brake assist control means for controlling the brake fluid pressure and the brake steering control and the brake assist control simultaneously satisfy the start condition, the first and second target control amounts are added, and the hydraulic control is performed based on the added amount. And a simultaneous control means for controlling the pressure control valve means.

According to the second aspect of the present invention, when the braking steering control and the brake assist control simultaneously satisfy the start condition,
There is no need to select any control, and both controls can be performed reliably.

In the first or second aspect, it is preferable that the first target control amount is a first target slip ratio and the second target control amount is a second target slip ratio. . According to this configuration, the brake steering control and the brake assist control can be easily and reliably performed.

[0012] In order to solve the above technical problem, a fourth aspect of the present invention is provided.
The vehicle braking control device according to the invention includes: a motion state detection unit that detects oversteer or understeer of the vehicle; and a control wheel selected from a plurality of wheels based on a determination result of the motion state detection unit. Brake steering control means for controlling the braking force of the selected wheel to suppress, brake operation amount detection means for detecting a value related to the operation amount of the brake pedal, based on the detection result of the brake operation amount detection means, Brake assist control means for controlling the braking force of each wheel to perform brake assist control, and when the brake steering control and the brake assist control simultaneously satisfy the start condition, the control by the brake steering control means for the selected wheel is performed. Priority control means for giving priority to control by the brake assist control means.

According to the fourth aspect of the present invention, when the brake steering control and the brake assist control simultaneously satisfy the start condition, the control by the brake steering control means is given priority over the control by the brake assist control means for the control overlapped wheels. Therefore, the running stability of the vehicle is secured with the highest priority.

[0014] In order to solve the above technical problem, a fifth aspect of the present invention is provided.
The vehicle braking control device according to the invention includes a wheel cylinder mounted on wheels of the vehicle to apply a braking force, a master cylinder generating hydraulic pressure in response to operation of a brake pedal, and connecting the master cylinder to the wheel cylinder. A main hydraulic pressure path, a modulator disposed in the main hydraulic pressure path to adjust the brake hydraulic pressure of the wheel cylinder, and a first on-off valve for opening and closing a main hydraulic pressure path between the modulator and the master cylinder. A hydraulic pump having a discharge side connected between the first on-off valve and the wheel cylinder, and a hydraulic pump for discharging brake fluid pressurized to the wheel cylinder; and a suction side of the hydraulic pump connected to the master cylinder. In a vehicle brake control device provided with an auxiliary hydraulic pressure path to be connected and a second opening / closing valve for opening and closing the auxiliary hydraulic pressure path, an oversteer or under Motion state detection means for detecting tare, and based on the detection result of the motion state detection means, controls the hydraulic pump, the first and second opening / closing valves, and the modulator to control oversteer suppression or understeer suppression. Brake steering control means for performing control, brake operation amount detection means for detecting a value related to the operation amount of the brake pedal, and at least the hydraulic pump and the first and second valves based on the detection result of the brake operation amount detection means. Brake assist control means for controlling the on / off valve of No. 2 to perform brake assist control, and when the brake assist control and the brake steering control simultaneously satisfy the start condition, the hydraulic pump, the first and second on / off valves Priority control means for giving priority to control by the brake steering control means over control by brake assist control means. Those were example.

According to the fifth aspect of the present invention, when the brake assist control and the brake steering control simultaneously satisfy the start condition, the control of the hydraulic pump and the first and second opening / closing valves by the brake steering control means is performed. Is given priority over the control by the brake assist control means, so that the hydraulic pump, the first and second on-off valves can be reliably controlled by the braking steering control means, and the hydraulic pump, the first and second on-off valves are controlled. It is clarified which control should be executed.

According to a fifth aspect of the present invention, as set forth in the sixth aspect of the invention, the braking steering control means selects a control wheel from a plurality of wheels based on a detection result of the motion state detecting means, and selects a control wheel of the selected wheel. (1) setting a target slip rate, controlling the modulator for the selected wheel based on the first target slip rate, controlling a brake fluid pressure of a wheel cylinder mounted on the selected wheel, the brake assist control means includes: Controlling a modulator for each wheel based on a second target slip ratio of each wheel, controlling a brake fluid pressure of a wheel cylinder mounted on each wheel, a braking control device for the vehicle includes a brake steering control and a brake assist control. Simultaneously satisfy the start condition, the first and second target slip rates are added, and the modulator for the selected wheel is controlled based on the added value. Further comprising a simultaneous control means, preferably.

According to this configuration, when the braking steering control and the brake assist control simultaneously satisfy the start condition, the braking steering control means controls the hydraulic pump and the first and second opening / closing valves. In addition, since the modulator for the control overlapping wheel is controlled based on the sum of the first target slip ratio for the brake steering control and the second target slip ratio for the brake assist control, both controls can be performed reliably.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of a vehicle motion control apparatus according to the present invention.
An engine EG is an internal combustion engine provided with a throttle control device TH and a fuel injection device FI,
In the throttle control TH, the accelerator pedal AP
The main throttle opening of the main throttle valve MT is controlled in accordance with the operation of. Also, the electronic control unit ECU
, The sub-throttle valve ST of the throttle control device TH is driven to control the sub-throttle opening, and the fuel injection device FI is driven to control the fuel injection amount. The engine EG of the present embodiment is connected to wheels FL and FR in front of the vehicle via a shift control device GS and a differential gear DF, and a so-called front-wheel drive system is configured.

Next, regarding the braking system, the wheels FL, F
Wheel cylinders Wfl, Wf for R, RL, RR, respectively
r, Wrl, Wrr are mounted, and a brake fluid pressure control device PC is connected to these wheel cylinders Wfl and the like. Wheel FL indicates the front left drive wheel as viewed from the driver's seat, wheel FR indicates the front right drive wheel, and wheel RL
Indicates a driven wheel on the rear left side, and wheel RR indicates a driven wheel on the rear right side. The brake fluid pressure control device PC is configured as shown in FIG. 2, which will be described later.

The wheels FL, FR, RL, and RR are provided with wheel speed sensors WS1 to WS4, which are connected to the electronic control unit ECU, and the rotational speed of each wheel, that is, the number of pulses proportional to the wheel speed. Is input to the electronic control unit ECU. Further, a brake switch BS which is turned on when the brake pedal BP is depressed, a pressure sensor PS for detecting a brake fluid pressure of a master cylinder MC described later, and a wheel F in front of the vehicle.
A front wheel steering angle sensor SSf for detecting a steering angle θf of L, FR,
A lateral acceleration sensor YG for detecting the lateral acceleration Gy of the vehicle and a yaw rate sensor YS for detecting the yaw rate γ of the vehicle are connected to the electronic control unit ECU. The yaw rate sensor YS detects the speed of change of the vehicle rotation angle (yaw angle) about a vertical axis passing through the center of gravity of the vehicle, that is, the yaw angular velocity (yaw rate), and outputs the detected yaw rate to the electronic control unit ECU as the actual yaw rate γ.

A steering angle control device (not shown) may be provided between the wheels RL and RR behind the vehicle. According to this, the wheel (not shown) is driven by a motor (not shown) according to the output of the electronic control unit ECU. It is also possible to control the steering angles of RL and RR.

The electronic control unit ECU of the present embodiment comprises processing units CP connected to each other via a bus.
A microcomputer MCP including a U, a memory ROM, a RAM, an input port IPT, an output port OPT, and the like is provided. Output signals from the wheel speed sensors WSl to WS4, the brake switch BS, the pressure sensor PS, the front wheel steering angle sensor SSf, the yaw rate sensor YS, the lateral acceleration sensor YG, and the like are input to an input port I via an amplifier circuit AMP.
It is configured to be input from the PT to the processing unit CPU. Further, a control signal is output from the output port OPT to the throttle control device TH and the brake fluid pressure control device PC via the drive circuit ACT. In the microcomputer MCP, the memory ROM stores programs used for various processes including the flowcharts shown in FIGS. 3 to 7, and the processing unit CPU executes the programs while an ignition switch (not shown) is closed. The memory RAM temporarily stores variable data necessary for executing the program. Note that a plurality of microcomputers may be configured for each control such as throttle control or a suitable combination of related controls, and may be electrically connected to each other.

FIG. 2 shows a brake fluid pressure control device BC, in which the master cylinder MC is boosted via a vacuum booster VB in response to the operation of the brake pedal BP, and the brake fluid in the master reservoir LRS is boosted. Thus, the master cylinder hydraulic pressure is output to the hydraulic system on the wheels FR, RL and the wheels FL, RR side. That is, a so-called X pipe is configured. Master cylinder MC
Is a tandem type master cylinder in which two pressure chambers are connected to respective brake hydraulic systems. That is, the first pressure chamber MCa is connected to the brake hydraulic system on the wheels FR and RL, and the second pressure chamber MCb is connected to the brake hydraulic system on the wheels FL and RR.

In the brake hydraulic system for the wheels FR and RL, the first pressure chamber MCa is connected to the wheel cylinders Wfr and Wrl via the main hydraulic passage MF and the branch hydraulic passages MFr and MFl, respectively. I have. In the main hydraulic path MF,
Normally-open 2-port 2-position solenoid valve SC1 (which functions as a so-called cut-off valve.
1). Further, the first pressure chamber MC
a is a check valve CV5 to be described later via an auxiliary hydraulic pressure path MFc.
Connected to CV6. The aforementioned hydraulic pressure sensor PS is connected to the auxiliary hydraulic pressure passage MFc, and detects the master cylinder hydraulic pressure Pmc. As a sensor for detecting the operation state of the brake pedal BP, a stroke sensor for detecting the stroke of the brake pedal BP may be used instead of the hydraulic pressure sensor PS.

The branch hydraulic pressure paths MFr and MFl are provided with normally open two-port two-position solenoid valves PC1 and PC2 (hereinafter simply referred to as valve PC1 and PC2). Further, check valves CV1 and CV2 are arranged in parallel with these, respectively. The check valves CV1 and CV2 allow only the flow of the brake fluid in the direction of the master cylinder MC, and the brake fluid in the wheel cylinders Wfr and Wrl passes through the check valves CV1 and CV2 and the on-off valve SC1. The master cylinder MC is returned to the master cylinder reservoir LRS. Therefore, when the brake pedal BP is released, the wheel cylinder Wf
The fluid pressure in r and Wrl can quickly follow the fluid pressure drop on the master cylinder MC side. Further, the wheel cylinder Wfr,
Discharge-side branch hydraulic pressure passages RFr, R connected to Wrl
Fl, normally closed 2-port 2-position solenoid on-off valve PC
5, PC6 (hereinafter simply referred to as on-off valves PC5, PC6)
Is disposed, and the discharge hydraulic pressure line RF where the branch hydraulic pressure lines RFr and RFl join is connected to the auxiliary reservoir RS1.

The auxiliary reservoir RS1 has check valves CV6 and CV6.
The suction side of the hydraulic pump HP1 is connected via CV5,
The discharge side is connected to the upstream side of the on-off valves PC1 and PC2 via the check valve CV7 and the hydraulic path MFp. The hydraulic pump HP1 is driven by a single electric motor M together with the hydraulic pump HP2, introduces brake fluid from the suction side, increases the pressure to a predetermined pressure, and outputs it from the discharge side. The auxiliary reservoir RS1 is connected to the master reservoir LR of the master cylinder MC.
It is provided independently of S, and can be called an accumulator, and has a piston and a spring, and is configured to be able to store a predetermined volume of brake fluid.

The master cylinder MC is provided with an auxiliary hydraulic pressure path MFc.
Is connected between the check valve CV5 and the check valve CV6 on the suction side of the hydraulic pump HP1. Check valve CV5
Is for blocking the flow of the brake fluid to the auxiliary reservoir RS1 and allowing the flow in the reverse direction. The check valves CV6 and CV7 regulate the flow of the brake fluid discharged through the hydraulic pump HP1 in a certain direction, and are usually integrally formed in the hydraulic pump HP1. Thus, the on-off valve SI1 shuts off communication between the master cylinder MC and the suction side of the hydraulic pump HP1 at the normal closed position shown in FIG. 2, and opens and closes the master cylinder MC and the hydraulic pump H at the open position.
It is switched so that the suction side of P1 communicates.

A relief valve RV1 and a check valve AV1 are arranged in parallel with the on-off valve SC1. The relief valve RV1 is connected from the master cylinder MC to the on-off valves PC1, P
Restrict the flow of brake fluid in the C2 direction,
1, when the brake fluid pressure on the PC2 side becomes higher than the master cylinder fluid pressure by a predetermined pressure or more, the master cylinder M
The brake fluid allows the flow of the brake fluid in the direction C (a so-called relative pressure relief valve), which can prevent the brake fluid discharged from the hydraulic pump HP1 from exceeding a predetermined pressure. The check valve AV1 permits the flow of the brake fluid in the direction of the wheel cylinders Wfr and Wrl, and prohibits the flow in the reverse direction. Due to the presence of the check valve AV1, the on-off valve S
Even when C1 is in the closed position, when the brake pedal BP is depressed, the brake fluid pressure in the wheel cylinders Wfr and Wrl is increased. A damper DP1 is provided on the discharge side of the hydraulic pump HP1, and a proportioning valve PV is provided in a hydraulic path leading to the wheel cylinder Wrl on the rear wheel side.
1 is interposed.

On the other hand, also in the brake hydraulic system on the wheels FL and RR side, similarly, a normally-open solenoid valve SC2, a normally-closed solenoid valve SI2, and a normally-open solenoid valve PC3, P
C4, normally closed solenoid on-off valves PC7, PC8, check valve CV
3, CV4, CV8 to CV10, relief valve RV2,
A check valve AV2, a reservoir RS2, a damper DP2, and a proportioning valve PV2 are provided. The hydraulic pump HP2 is driven by the electric motor M to operate the hydraulic pump HP1.
Driven with

The electric motor M, on-off valves SC1, SC
2, SI1, SI2 and on-off valves PC1 to PC8 are
Drive control is performed by the electronic control unit ECU, and various controls such as braking steering control (oversteer suppression control or understeer suppression control), brake assist control, anti-skid control, longitudinal braking force distribution control, and traction control are performed.

In the present embodiment configured as described above, a series of processes such as braking steering control, brake assist control, anti-skid control, and the like are performed by the electronic control unit ECU, and an ignition switch (not shown) is opened. Then, a program corresponding to the flowcharts of FIGS. 3 to 8 is executed.

FIG. 3 shows the operation of the braking control. First, at step 101, the microcomputer MCP is initialized and various calculated values are cleared. Then step 1
02, the detection signals of the wheel speed sensors WS1 to WS4, the detection signal of the brake switch BS, the pressure sensor P
S detection signal (master cylinder hydraulic pressure Pmc), front wheel steering angle sensor SSf detection signal (steering angle θf), yaw rate sensor YS detection signal (actual yaw rate γ), and lateral acceleration sensor YG detection signal (ie, actual lateral Acceleration, which is represented by Gya).

Then, the process proceeds to a step 103, wherein the master cylinder hydraulic pressure change ratio D is determined according to the detection signal of the pressure sensor PS.
Pmc is calculated. Next, at step 104, the wheel speed Vw ** of each wheel is calculated, and the wheel speed Vw ** of each wheel is differentiated to obtain the wheel acceleration DVw ** of each wheel.
Is calculated, noise is removed by a filter (not shown), and the normal wheel acceleration FDVw ** of each wheel is obtained. Next, in step 105, based on the wheel speed Vw ** of each wheel, the estimated vehicle speed at the center of gravity of the vehicle (hereinafter referred to as the center-of-gravity position body speed) Vso is Vso = MAX.
(Vw **) and an estimated vehicle speed at each wheel position (hereinafter referred to as each wheel position vehicle speed) Vso **
Is required. Then, if necessary, normalization is performed on each wheel position vehicle speed Vso ** in order to reduce an error based on a difference between the inner and outer wheels when the vehicle turns. That is, the normalized vehicle speed NVso ** is calculated as NVso ** = Vso ** (n) -ΔVr ** (n). Here, ΔVr ** (n) is a correction coefficient for turning correction, and is set, for example, as follows. That is, the correction coefficient ΔVr ** (** represents each wheel FR, etc., especially FW is the front two wheels,
RW represents the rear two wheels) is the turning radius R and γ · Vso of the vehicle.
Based on FW (= lateral acceleration Gya), it is set according to a map (not shown) for each wheel except for the reference wheel. For example, based on ΔVrFL, this is set to 0,
ΔVrFR is set according to the inner / outer wheel difference map, and ΔVrRL
Is set according to the inside-to-outside wheel difference map, and ΔVrRR is set according to the outside-to-outside wheel difference map and the inside-outside wheel difference map. Further, the vehicle body acceleration DVso in the front-rear direction at the position of the center of gravity of the vehicle (hereinafter referred to as the center-of-gravity position body acceleration) DVso is calculated by differentiating the center-of-gravity position body speed Vso. Next, at step 106, the actual slip ratio Sa ** of each wheel is Sa ** = based on the wheel speed Vw ** of each wheel and the estimated vehicle speed Vso ** of each wheel obtained at steps 104 and 105. (Vso **-V
w **) / Vso **.

Next, at step 107, based on the center of gravity position body acceleration DVso and the actual lateral acceleration Gya detected by the lateral acceleration sensor YG, the road surface friction coefficient μ is approximately
It is estimated as (DVso2 + Gya2) 1/2. The road surface friction coefficient μ and the wheel cylinder hydraulic pressure Pw of each wheel
The road surface friction coefficient μ ** at each wheel position may also be calculated based on the estimated value of **. Subsequently, at step 108, based on the detection signal (actual yaw rate γ) of the yaw rate sensor YS, the detection signal (actual lateral acceleration Gya) of the lateral acceleration sensor YG, and the center-of-gravity position vehicle speed Vso, the vehicle body side slip angular velocity becomes Dβ =
Gya / Vso-γ. Then, Step 1
At 09, the vehicle body slip angle β is obtained as β = ∫Dβdt. Here, the vehicle body slip angle β is an angle representing the slip of the vehicle body in the traveling direction of the vehicle, and the vehicle body slip angular velocity Dβ is a differential value dβ / dt of the vehicle body slip angle β. The vehicle body slip angle β can be obtained as β = tan −1 (Vy / Vx) based on the ratio of the vehicle speed Vx in the traveling direction to the vehicle speed Vy in the lateral direction perpendicular to the traveling direction.

Next, the routine proceeds to step 110, where brake assist control calculation is performed as described later. Then, in step 111, a braking steering control calculation is performed as described later, and a target slip ratio to be provided for the braking steering control is set as described later. The brake fluid pressure control device BC is accordingly controlled, and the braking force on each wheel is controlled. This braking steering control is superimposed on control in all control modes described later. After the brake steering control calculation, the process proceeds to step 112, where it is determined whether or not the anti-skid control start condition is satisfied. If it is determined that the start condition is satisfied and the anti-skid control start is required during the brake steering, the process proceeds to step 113. The control mode is set to perform both the brake steering control and the anti-skid control.

If it is determined in step 112 that the anti-skid control start condition is not satisfied, the process proceeds to step 114, where it is determined whether the front-rear braking force distribution control start condition is satisfied. When it is determined that the braking force distribution control is started, the routine proceeds to step 115, where a control mode for performing both the braking steering control and the longitudinal braking force distribution control is set. Is satisfied or not. If it is determined that the traction control is started during the brake steering control, a control mode for performing both the brake steering control and the traction control is set in step 117. If the control mode is not satisfied, the process proceeds to step 118 and the brake steering control start condition is set. It is determined whether the condition is satisfied. If it is determined that the braking steering control is to be started, step 119 is performed.
Is set to the braking steering control mode. Then, after performing hydraulic servo control in step 120 based on these control modes, the process returns to step 102. Step 1
If it is not determined at 18 that the braking steering control has been started, the routine proceeds to step 121, where all the solenoids are turned off. Note that, based on steps 113, 115, 117, and 119, the sub-throttle opening of the throttle control device TH is adjusted according to the motion state of the vehicle, if necessary, to reduce the output of the engine EC and limit the driving force. .

In the anti-skid control mode, the wheels are prevented from locking during braking of the vehicle.
The braking force applied to each wheel is controlled. In the front / rear braking force distribution control mode, the distribution of the braking force applied to the rear wheels to the braking force applied to the front wheels is controlled so as to maintain stability of the vehicle during braking of the vehicle. In the traction control mode, a braking force is applied to the drive wheels and a throttle control is performed so as to prevent the drive wheels from slipping when the vehicle is driven, and the drive force for the drive wheels is controlled by these controls. You.

Next, referring to FIG. 4, step 11 in FIG.
Details of the brake assist control calculation at 0 will be described.

First, at step 201, it is determined whether or not the brake assist control flag FL is the flag F1 or the flag F2.
Here, the flag F1 indicates that the start specifying control is being performed, and the flag F2 indicates that this control is being performed. At step 202, it is determined whether or not the BA control start condition is satisfied. If so, the process proceeds to step 203, where the control flag FL is set to the start specific control in-progress flag F1. Here, the condition for starting the brake assist control is determined by the detected hydraulic pressure Pm of the hydraulic pressure sensor PS.
c is greater than or equal to a predetermined value, and the detected fluid pressure change rate D
Pmc is equal to or higher than a predetermined ratio.

Subsequently, from step 203 to step 20
Proceeding to 4, the start specific control calculation is performed. That is, the duty Dis of the on-off valve SI * provided for the start specifying control and the execution time Ts of the start specifying control are set. In particular,
The duty Dis of the opening / closing valve SI * is selected from a map (not shown) according to the master cylinder hydraulic pressure Pmc and the change rate DPmc of the master cylinder hydraulic pressure at the time when the control start is required. The duty Dis of the on-off valve SI * is set to be larger as the master cylinder fluid pressure Pmc is higher, and the duty Dis of the on-off valve SI * is set to be larger as the master cylinder fluid pressure change rate (increase rate) DPmc is larger. Further, the execution time Ts of the start specifying control is determined by setting the target brake fluid amount Vc to be supplied to the wheel cylinder WC to the hydraulic pump H in consideration of the duty Dis of the on-off valve SI * and the like.
The time (P) divided by the discharge amount Vp per unit time of P and the fixed time Tc (for example, 1 sec) are set to the smaller time.

Then, the routine proceeds to step 205, where the duty of the opening / closing valve SI * for the specific start control is set to the value selected in step 204, and the duty of the opening / closing valve SC * is set to 100%. Then, step 20
At 6, it is determined whether or not the above-mentioned execution time Ts has elapsed after the start of the brake assist control. If the execution time Ts has not elapsed, the process returns to the main routine of FIG. 3 if it has not elapsed, and if it has elapsed, the control flag FL becomes F2 at step 207. After the setting, the process returns to the main routine of FIG.

On the other hand, if it is determined in step 201 that the control flag FL is the start-specifying control-in-progress flag F1 or the main control-in-progress flag F2, the flow advances to step 208 to determine whether or not the brake assist control end condition is satisfied (ie, the (Necessity of termination) is determined. Here, the brake switch BS is turned off, the vehicle body speed Vso at the center of gravity position is equal to or lower than a predetermined speed, and the master cylinder hydraulic pressure Pmc is set to a predetermined lower limit Pa (for example, 1MP).
a) When any one of the following conditions is satisfied, it is determined that control termination is necessary. If it is determined in step 208 that the termination condition is not satisfied, the process proceeds to step 209, and it is determined whether the control flag FL is the start-specific-control-in-progress flag F1. If so, the processing of steps 205 to 207 is executed again. If it is determined in step 209 that the control flag FL is not F1, the control flag FL is the main control flag F2.
Then, the process proceeds to S13, where the control process is executed.

First, at step 210, a vehicle deceleration Δg corresponding to a predetermined hydraulic pressure for brake assist control is added to a vehicle deceleration Gm corresponding to the master cylinder hydraulic pressure Pmc, and the target deceleration G of the vehicle is obtained. * Is set. That is, the target deceleration G * according to the operation amount of the brake pedal BP is set. Subsequently, the routine proceeds to step 211, where the difference between the target deceleration G * of the vehicle and the vehicle deceleration DVso at the position of the center of gravity used as the actual deceleration is calculated.

Next, the routine proceeds to step 212, where a brake assist control amount is calculated using the deceleration deviation ΔG as a control deviation. That is, the duty (percentage of the energization time) Di, Dc of the on-off valves SI *, SC * is set based on the deceleration deviation ΔG using the graph of FIG. Specifically, on the pressure increasing side (the deceleration deviation ΔG is positive), the duty Di of the on-off valve SI * is set to be proportional to the deceleration deviation, and the duty Dc of the on-off valve SC * is close to 100%. It is set to a constant value and is set to a substantially closed position. Here, when the deceleration deviation 0 <ΔG <Gk, the duty D of the on-off valve SI *
i is set to 0%, and the on-off valve SI * is set to the closed position. On the other hand, on the pressure reduction side (the deceleration deviation ΔG is negative), the on-off valve SC *
Is set so as to be proportional to the deceleration deviation, the duty Di of the on-off valve SI * is set to a constant value near 0%, and is set to the substantially closed position. Also, the on-off valve SI
A predetermined limit is added to the duty Di of *. That is, even if the deceleration deviation ΔG is large, the on-off valve SI
The duty Di of * is set so as not to exceed a predetermined upper limit value Dup. This is to prevent as much as possible an excessive amount of brake fluid from being sucked into the hydraulic pump HP from the master cylinder MC.
And the fluctuation of the output signal of the hydraulic pressure sensor PS can be suppressed as much as possible.

Subsequently, the routine proceeds to step 213, where a brake assist braking force distribution control amount calculation is performed. In the brake assist braking force distribution control, when a predetermined start condition is satisfied during the brake assist control, the braking force distribution between the wheels is adjusted to maintain a stable braking state.
Here, the target slip ratio of each wheel is set according to the deceleration deviation ΔG. Here, the start condition is a case where the absolute value of the combined acceleration of the estimated vehicle body acceleration DVso and the actual lateral acceleration Gya of the vehicle is equal to or higher than a predetermined value, and the master cylinder hydraulic pressure Pmc is equal to or higher than the predetermined hydraulic pressure. The target slip ratio used for the brake assist braking force distribution control is a fixed value (for example, a target slip ratio of 10
%, A target rear wheel slip rate of 5%). Thereafter, the process returns to the main routine of FIG.

On the other hand, when it is determined in step 208 that the brake assist control end condition is satisfied, the routine proceeds to step 214, where the control flag FL is set to the end specifying control in-progress flag F3. Next, in step 215, an end specifying control operation is executed. That is, the change rate of the master cylinder hydraulic pressure at the time of the control end necessity determination (pressure reduction rate)
Open / close valve SC * provided for end specific control according to DPmc
Is set. The duty Dce of the on-off valve SC * is increased when the rate of decrease of the master cylinder hydraulic pressure is large in order to reflect the driver's will. Further, the execution time Te of the end specifying control is set to a fixed time (for example, 0.2 sec).

Then, the process proceeds to a step 216, wherein the duty of the on-off valve SC * for the end specifying control is set to the value selected in the step 215, and the duty of the on-off valve SI * is set to 0%. Next, at step 217, the execution time Te after the brake assist control ends.
Is determined. If not, the process returns to the main routine of FIG.
After the control flag FL is set to F0,
Return to the main routine.

On the other hand, if it is determined in step 202 that the BA control start condition is not satisfied (that is, the end specifying control is being performed or not controlled), the process proceeds to step 219, where the control flag FL is changed to the end specifying control flag F3. It is determined whether the answer is NO, and if so, steps 216 to 218 are executed again, and then the process returns to the main routine of FIG. Step 2
If it is determined in step 19 that the control flag FL is not the end-specifying-control-in-progress flag F3, it means that control is not to be performed, and the process returns to the main routine in FIG.

Next, referring to FIG. 5, step 11 in FIG.
1 will be described in detail. Here, the braking steering control includes oversteer suppression control and understeer suppression control, and a target slip ratio corresponding to the oversteer suppression control and / or the understeer suppression control is set for the control wheel.

First, in steps 301 and 302, the start and end of the oversteer suppression control and the understeer suppression control are determined.

The determination of the start / end of the oversteer suppression control in step 301 is performed based on whether or not the vehicle is in the control area indicated by the oblique lines in FIG. That is, if the values of the vehicle body sideslip angle β and the vehicle body sideslip angular velocity Dβ at the time of the determination enter the control region, the oversteer suppression control is started, and if the vehicle leaves the control region, the oversteer suppression control is ended.
The control is performed as indicated by the arrow curve in FIG. Then, the boundary between the control region and the non-control region (two-dot chain line in FIG. 10)
The braking force of each wheel is controlled such that the target control amount increases as the vehicle departs from the control region.

On the other hand, the start / end determination of the understeer suppression control is performed based on whether or not the vehicle is in a control area indicated by oblique lines in FIG. That is, at the time of determination, according to the change of the actual lateral acceleration Gya with respect to the target lateral acceleration Gyt, understeer suppression control is started when the vehicle deviates from the ideal state indicated by the one-dot chain line and enters the control region. Is ended, and control is performed as indicated by the arrow curve in FIG.

Subsequently, it is determined in step 303 whether or not the oversteer suppression control is being controlled, and if not, it is determined in step 304 whether or not the understeer suppression control is being controlled. If not, the process returns to the main routine of FIG. If it is determined in step 304 that the understeer suppression control is being performed, the process proceeds to step 305, in which both front wheels and the turning inside rear wheel are selected as control wheels, and their target slip rates are Svufo, Svufi, Sv, respectively.
Set to vuri. The slip ratio (S) shown here
The sign "v" represents "target", which is compared with "a" representing "actual measurement" described later. "u" indicates "understeer suppression control", "f" indicates "rear wheel", and "r" indicates "rear wheel".
Where "o" represents "outside" and "i" represents "inside".

On the other hand, if it is determined in step 303 that the oversteer suppression control is being performed, the process proceeds to step 306, and it is determined whether the understeer suppression control is being performed. If not, the process proceeds to step 307. In step 307, the turning outer front wheel and the turning inner rear wheel are selected as control wheels, and their target slip ratios are respectively set to Svef.
o, set to Sveri. “E” represents “oversteer suppression control”.

If it is determined in step 306 that the understeer suppression control is also being performed, the process proceeds to step 308, where the target slip ratio of the front wheel on the outside of the turn is set to Svefo, and the target slip ratio of the front and rear wheels on the inside of the turn is set to Svufi, Svuri. Is done. That is, when the oversteer suppression control and the understeer suppression control are performed at the same time, the front outside wheel of the turning is set to the target slip ratio of the oversteer suppression control, and the front and rear inside wheels are set to the target slip ratio of the understeer suppression control.

In any case, the turning outer rear wheel (ie, the driven wheel in the front wheel drive vehicle) is not controlled because the center of gravity position body speed Vso is set.

The vehicle slip angle β and the vehicle slip angular velocity Dβ are used to set the target slip ratio for the oversteer suppression control. That is, Svefo = K1 · β + K2
Dβ, Sveri = K3 · β + K4 · Dβ Here, K1 to K4 are constants, the target slip ratio Svefo of the turning outer front wheel is set to a value for controlling the pressing direction (direction in which the braking force is increased), and the target slip ratio Sveri of the turning inner rear wheel is , Is set to a value for controlling the pressure reduction direction (direction for reducing the braking force). Therefore, when the brake pedal is not operated, Sveri = 0.

The difference between the target lateral acceleration Gyt and the actual lateral acceleration Gya is used for setting the target step rate in the understeer suppression control. This target lateral acceleration Gyt is G
It is obtained based on yt = γ (θf) · Vso. here,
γ (θf) is γ (θf) = {(θf / N) · L} · Vso
/ (1 + Kh · Vso2), where Kh is a stability factor, N is a steering gear ratio, and L is a wheelbase.

The target slip ratio for the understeer suppression control is set as follows based on the deviation ΔGy between the target lateral acceleration Gyt and the actual lateral acceleration Gya. That is, S
vufo and Svuf are set as K5.ΔGy and K6.ΔGy, respectively. These constants K5 and K6 are set to values for controlling the pressing direction during non-braking, and set to 0 during braking. Sturi
Is set to K7.DELTA.Gy, and the constant K7 is set to a value for controlling the pressing direction regardless of the operation of the brake pedal.

Next, the hydraulic servo control of step 120 in FIG. 3 will be described in detail with reference to FIGS. 6 and 7. Here, the slip ratio servo control of the wheel cylinder hydraulic pressure is performed for each wheel.

First, in step 401, it is determined whether or not the braking steering control mode is set (that is, whether or not the starting condition of the braking steering control is satisfied). If the mode is the braking steering control mode, the process proceeds to step 402, and step 30 in FIG.
The target slip ratio Sv ** of the selected wheel set at 5,307,308 is read out, and is read as the target slip ratio St *.
* On the other hand, if the mode is not the braking steering control mode, the routine proceeds to step 403, where the target slip ratio St ** is set to 0.

Next, the routine proceeds to step 404, where it is determined whether or not the brake assist braking force distribution control is being performed. If so, the routine proceeds to step 405, where the target slip ratio St ** is set to the brake set in step 213 in FIG. After the target slip ratio St ** for the assist braking force distribution control is added to update the target slip ratio St **, the routine proceeds to step 406. If the brake assist braking force distribution control is not being performed,
Proceed directly to step 406. And step 40
At 6, the target slip ratio ΔSs * for anti-skid control
*, The target slip ratio ΔSd ** for longitudinal braking force distribution control,
And the target slip ratio ΔSr ** for traction control is added, and the target slip ratio St ** is updated. It is to be noted that ΔSs ** = 0 when not in the anti-skid control mode, ΔSd ** = 0 when not in the longitudinal braking force distribution control mode, and ΔSr ** = 0 when not in the traction control mode.

Next, in step 407, the slip ratio deviation ΔSt ** of the controlled wheel is calculated, and in step 408, the vehicle body acceleration deviation ΔDVso ** is calculated. Specifically, in step 407, the difference between the target slip rate St ** of the control wheel and the actual slip rate Sa ** is calculated, and the slip rate deviation ΔSt ** is ΔSt ** = St ** − Sa
Calculated as **. Also, in step 408,
Center of gravity position body acceleration DVso and wheel acceleration DV of control wheels
The difference of w ** is calculated, and the vehicle body acceleration deviation ΔDVso ** is obtained. At this time, the actual slip ratio Sa ** of each wheel and the vehicle body acceleration deviation ΔDVso ** are calculated differently depending on a control mode such as anti-skid control, traction control, etc., but the description thereof will be omitted.

Subsequently, the routine proceeds to step 409 in FIG. 7, in which one parameter Y ** used for brake hydraulic pressure control in each control mode is calculated as Gs ** · ΔSt **. Here, Gs ** is a gain and is set according to the vehicle body slip angle β. In step 410, another parameter X ** to be provided for the brake fluid pressure control is Gd ** · ΔDV
Calculated as so **. At this time, the gain Gd ** is a constant value.

Thereafter, the routine proceeds to step 411, where a hydraulic control mode is set for each selected wheel according to the control map shown in FIG. 12 based on the parameters X ** and Y **. In FIG. 12, respective regions of a rapid pressure reduction region, a pulse pressure reduction region, a holding region, a pulse pressure increase region, and a rapid pressure increase region are set in advance, and any region is determined according to the values of the parameters X ** and Y **. Is determined. In the non-control state, the hydraulic control mode is not set (the solenoid is off).

When the area determined this time in step 411 switches from pressure increase to pressure reduction or pressure reduction to pressure increase with respect to the area determined last time, the falling or rising of the brake fluid pressure is smoothly performed. In step 412, pressure increase / decrease compensation processing is performed. For example, when switching from the rapid pressure reduction mode to the pulse pressure increase mode, rapid pressure increase control is performed, and the time is determined based on the duration of the immediately preceding rapid pressure reduction mode. Next, in step 413, the on-off valves SI * and S
The driving process of C * is performed. Finally, in step 414, the control valve PC * is driven in accordance with the hydraulic control mode and the pressure increase / decrease compensation processing to control the braking force of each wheel.

Referring to FIG. 8, the driving process of the on-off valves SI * and SC * will be described.

First, in step 501, it is determined whether or not the braking steering control is being performed (the start condition of the braking steering control is satisfied). If so, the process proceeds to step 502, where the hydraulic pressure mode applied to the wheel to be controlled is set. Is determined. If the hydraulic pressure mode is the rapid pressure increase mode, the process proceeds to step 503, and the on-off valve SI * (for example, SI1) for the control wheel is turned on to be in the open position. If the mode is the pulse pressure increasing mode, step 504 is executed.
Then, the on-off valve SI * for the control wheel is turned on (opened) substantially in synchronization with the pressure increase in the pulse pressure increase mode. Specifically, the on-off valve SI * is turned on for a predetermined time before the boosted pressure output in the pulse boosting mode, and is turned off when the boosted pressure output ends. On the other hand, in the case of the holding mode, the pulse depressurization mode, and the rapid depressurization mode, the process proceeds to step 505, and the on-off valve SI * for the control wheel is turned off (closed).

On the other hand, if it is determined in step 501 that the brake steering control is not being performed, the process proceeds to step 506, where it is determined whether the brake assist control is being performed (the start condition of the brake steering control is satisfied). If the brake assist control is being performed, the routine proceeds to step 507, where it is determined whether or not the braking force distribution control is being performed. If the brake assist braking force distribution control is being performed, the process proceeds to step 50 similarly to the case of the brake steering control.
In step 2, the hydraulic mode for each wheel is determined, and steps 503 to 505 are executed according to the hydraulic mode. When it is determined in step 507 that the brake assist braking force distribution control is not being performed, the process proceeds to step 508, and the on-off valve SI * is duty-driven based on the on-off valve SI * duty Di set in step 212 in FIG. You.

After steps 503 to 505 and 508,
Proceeding to step 509, it is determined again whether the brake steering control is being performed. If the brake steering control is being performed, the process proceeds to step 510, where the on-off valve SC * for the control wheel is turned on (closed),
Thereafter, the flow advances to step 512. If the brake steering control is not being performed, that is, if the brake assist control is being performed, step 51 is executed.
1 and the on-off valve S set in step 212 of FIG.
After the on-off valve SC * is duty-driven based on the duty Dc for C *, the process proceeds to step 512. Then, in step 512, the motor M is turned on.

If it is determined in step 506 that the brake assist control is not being performed, the routine proceeds to step 513, where the on-off valve SI * is turned off (closed).
Then, the on-off valve SC * is turned off (open), and finally, the process proceeds to step 515, where the motor M is turned off.

Here, if the start conditions of both the brake steering control and the brake assist control are satisfied, it is determined as YES in step 501, and steps 503 to 503 are performed according to the hydraulic mode for the control wheels. As in 505, the on-off valve SI * for the control wheel is driven. Then, step 5
09 is determined as YES, and at step 510, the on-off valve SC * for the control wheel is turned on (closed). Further, at step 512, the motor M is also turned on. in this way,
For the on-off valves SI *, SC * and the motor M, the control by the brake steering control has priority over the control by the brake assist control.

[0074]

According to the first aspect of the invention, when the braking steering control and the brake assist control simultaneously satisfy the start condition, the first target control amount for the brake steering control and the second target control amount for the brake assist control are provided. Since the braking force of the control overlap wheel is controlled based on the added amount of the control amount, it is not necessary to select any control, and both controls can be performed reliably.

According to the fourth aspect of the present invention, when the braking steering control and the brake assist control simultaneously satisfy the start condition, the control by the brake steering control means is given priority over the control by the brake assist control means for the control overlapped wheels. Therefore, the running stability of the vehicle can be secured with the highest priority.

According to the fifth aspect of the present invention, when the brake assist control and the brake steering control simultaneously satisfy the start condition, the control of the hydraulic pump and the first and second opening / closing valves by the brake steering control means is performed. Is given priority over the control by the brake assist control means, so that the hydraulic pump, the first and second on-off valves can be reliably controlled by the braking steering control means, and the hydraulic pump, the first and second on-off valves are controlled. It is clarified which control should be executed.

According to the invention of claim 6, when the braking steering control and the brake assist control simultaneously satisfy the start condition, the control by the braking steering control means for the hydraulic pump and the first and second opening / closing valves is performed. In addition, the modulator for the overlapped wheels is controlled based on the sum of the first target slip ratio for the brake steering control and the second target slip ratio for the brake assist control. it can.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a braking control device of the present invention.

FIG. 2 is a configuration diagram illustrating an example of a brake fluid pressure control device of FIG. 1;

FIG. 3 is a flowchart showing an entire vehicle braking control according to the embodiment of the present invention.

FIG. 4 is a flowchart illustrating details of a brake assist control calculation in FIG. 3;

FIG. 5 is a flowchart showing details of a brake steering control calculation in FIG. 3;

FIG. 6 is a flowchart showing details of hydraulic servo control in FIG. 3;

FIG. 7 is a flowchart showing details of hydraulic servo control in FIG. 3;

8 is a flowchart showing details of the on-off valve SI *, SC * drive processing of FIG. 7;

FIG. 9 is a graph showing the relationship between the duty of the on-off valves SI * and SC * used for brake assist control and the deceleration deviation in the present embodiment.

FIG. 10 is a graph showing a control region of oversteer suppression control according to the embodiment.

FIG. 11 is a graph showing a control region of understeer suppression control according to the embodiment.

FIG. 12 is a graph showing a relationship between a parameter used for brake hydraulic pressure control and a hydraulic mode in the present embodiment.

[Explanation of symbols]

 FR, FL, RR, RL Wheel Wfr, Wfl, Wrr, Wrl Wheel cylinder BP Brake pedal MC Master cylinder (hydraulic pressure generator) MF Main hydraulic path SC * On-off valve (first on-off valve) HP Hydraulic pump MFc Auxiliary Hydraulic path SI * On-off valve (second on-off valve) PC1 to PC8 On-off valve (modulator) ECU Electronic control unit

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Satoshi Yokoyama 2-1-1 Asahi-cho, Kariya-shi, Aichi Prefecture Aisin Seiki Co., Ltd.

Claims (6)

[Claims] 1. A motion state detection means for detecting oversteer or understeer of a vehicle, and a control wheel is selected from a plurality of wheels based on a detection result of the motion state detection means, and a first target control for the selected wheel is performed. A braking steering control means for controlling a braking force of the selected wheel based on the first target control amount to suppress oversteer or understeer of the vehicle, and detecting a value relating to an operation amount of the brake pedal. Brake operation amount detection means, brake assist control means for performing brake assist control based on the detection result of the brake operation amount detection means, and controlling braking force of each wheel based on a second target control amount, braking steering control and braking When the start condition is simultaneously satisfied with the assist control, the first and second target control amounts are added, and based on the added amount, the control overlap vehicle A braking control device for a vehicle, comprising: a simultaneous control unit that controls a braking force of a wheel. 2. A plurality of wheel cylinders mounted on a plurality of wheels of a vehicle for applying a braking force, a hydraulic pressure generating device for generating a hydraulic pressure in response to an operation of a brake pedal, the hydraulic pressure generating device and the wheel A hydraulic pressure control valve disposed between the cylinders for controlling a brake hydraulic pressure of the wheel cylinder; a motion state detecting means for detecting oversteer or understeer of the vehicle; and Selecting a control wheel from a plurality of wheels, setting a first target control amount for the selected wheel, and controlling the hydraulic pressure control valve means based on the first target control amount to suppress oversteer or understeer of the vehicle. Brake steering control means for controlling the brake fluid pressure of a wheel cylinder mounted on the selected wheel, and detecting a value related to the operation amount of the brake pedal. A brake operating amount detecting means for,
Brake assist control means for performing brake assist control based on a detection result of the brake operation amount detection means, controlling the hydraulic pressure control valve means based on a second target control amount, and controlling brake hydraulic pressure of each wheel cylinder; Simultaneous control means for adding the first and second target control amounts when the brake steering control and the brake assist control simultaneously satisfy the start condition, and controlling the hydraulic pressure control valve means based on the added amount. Vehicle braking control device. 3. The braking control device for a vehicle according to claim 1, wherein the first target control amount is a first target slip ratio, and the second target control amount is a second target slip ratio. 4. A vehicle for detecting oversteer or understeer of a vehicle, and selecting a control wheel from a plurality of wheels based on a result of the determination by the exercise condition detector to suppress oversteer or understeer. Braking steering control means for controlling the braking force of the selected wheel; brake operation amount detecting means for detecting a value relating to the operation amount of the brake pedal; and braking force for each wheel based on the detection result of the brake operation amount detecting means. Brake assist control means for performing brake assist control by controlling
A braking control unit that includes a priority control unit that gives priority to the control by the brake steering control unit over the control by the brake assist control unit for the selected wheel when the brake steering control and the brake assist control simultaneously satisfy the start condition. Control device. 5. A wheel cylinder mounted on wheels of a vehicle for applying a braking force, a master cylinder for generating a hydraulic pressure in response to an operation of a brake pedal, and a main hydraulic passage connecting the master cylinder to the wheel cylinder. A modulator disposed in the main hydraulic path and adjusting a brake hydraulic pressure of the wheel cylinder; a first on-off valve for opening and closing a main hydraulic path between the modulator and the master cylinder;
A discharge side is connected between the first on-off valve and the wheel cylinder, and a hydraulic pump that discharges brake fluid that has been pressurized to the wheel cylinder is connected to the master cylinder, and a suction side of the hydraulic pump is connected to the master cylinder. And a second on-off valve for opening and closing the auxiliary hydraulic path, a motion state detecting means for detecting oversteer or understeer of the vehicle, and a motion state detecting means. Brake steering control means for controlling the hydraulic pump, the first and second opening / closing valves, and the modulator to perform oversteer suppression control or understeer suppression control based on the determination result, and an operation amount of the brake pedal Brake operation amount detection means for detecting a value regarding the hydraulic pump, based on a detection result of the brake operation amount detection means. A brake assist control unit that controls the first and second opening / closing valves to perform brake assist control; and if the brake assist control and the brake steering control simultaneously satisfy a start condition, the hydraulic pump and the first And a priority control means for giving priority to control by the brake steering control means over control by the brake assist control means for the second on-off valve. 6. The braking steering control unit according to claim 5, wherein the braking steering control unit selects a control wheel from a plurality of wheels based on a detection result of the motion state detection unit, and sets a first target slip ratio of the selected wheel. Controlling the modulator for the selected wheel based on the first target slip ratio;
Controlling a brake fluid pressure of a wheel cylinder mounted on the selected wheel, the brake assist control means controlling a modulator for each wheel based on a second target slip ratio of each wheel, and controlling a wheel mounted on each wheel. Controlling the brake fluid pressure of the cylinder; the braking control device for the vehicle, when the braking steering control and the brake assist control simultaneously satisfy the start condition,
A braking control apparatus for a vehicle, further comprising: simultaneous control means for adding the first and second target slip ratios and controlling the modulator for the overlapped control wheel based on the added value.